Duncan, the makers of the classic Yo-Yo, include on their site the Teachers' Yo-Yo Lesson Planner.
That's right. In five 35-40 minute lessons You can demonstrate pendulums, potential and kinetic energy, and even set up an experiment to test a hypothesis. Wheee!
(I've been looking at a lot of yo-yo sites tonight; kiddo expressed an interest in a yo-ball for Christmas, and I can't find one for sale online. Gah.)
tags: classic toys, education